Technologies for the Near Future

RDF

The Resource Description Framework is the W3C's new technology for
metadata, which is data about other data. It extends the functions that
were introduced with PICS, of making statements about things on the Web
that can be interpreted automaticaly by machines.

How does it work?

RDF statements are written in XML, encoding a statement of the type X
has relationship Y to Z. The W3C Recommendation for RDF model and syntax
defines two equivalent methods of expressing RDF. Because this is
designed to be produced and consumed by software rather than people, the
syntax may seem a little like magic- it consists of URIs and little bits
of glue code. But the strength is that by describing things in terms of
URIs it is possible to have each part of an assertion as a first class
object, about which further assertions can be made.

Who is using it?

Machines and software. RDF is used to provide sophisticated control
over access to W3C pages, in engines for searching the web, in
classifying information for cataloguing systems. RDF is also used to
build databases that are distributed over the Web.

Where is it going?

Experimental uses of RDF include

adding it to SVG images to describe relationships between parts of
a diagram, so the diagram can be presented in a different manner by
software (an alternative understanding is that some SVG can be added
to some RDF to represent it graphically...)

describing privacy policies and accceptable use of user's private
information, in P3P (the Platform for Privacy Preferences
Project)